This invention relates to a semiconductor relay circuits and, more particularly, to a semiconductor relay circuit in which a light-emitting diode converts an input signal to a light signal, a photovoltaic diode array optically coupled to the light-emitting diode converts the light signal to an electrical signal which is used for driving a metal-oxide-semiconductor field effect transistor (hereinafter, referred to simply as "MOS FET") as an output means to obtain a contact signal as an output.